Spiral Staircase

Spiral Staircase?  Well, that's what it started off as.

The staircase goes around the outside of the town's water storage tank.
( Previously blipped here: 
https://www.blipfoto.com/entry/2828780593670524102
and here: https://www.blipfoto.com/entry/3092994720331202591 )
I re-photographed a section of it, converted to mono, distorted it using polar coordinates with two different settings and finally combined them in 'difference' mode.

I liked the middle section - the lower part reminded me of Sydney Opera House (inverted).